I am not a big fan of moving
either post #5 or post #6 approximately 8” or more when only placed within a
span of 18.75” due to the potential for increased pocketing when striking just
upstream from this location and near asymmetric transition segment. Instead, I
would rather use the dual-post straddle and beam system that was developed for
Erik Emerson and the Wisconsin DOT in a recent research study. Have you
considered this system?

Now, as a last resort, I maybe
could live with the post shift method if the transition were extended more
upstream to include another thrie beam panel (6 ft – 3 in.) and more ¼-post
spacings to mitigate any concerns with a shifted post of 8”.

I will ask that Bob/Scott
comment as well. Please let me know if you have any questions related to the
information noted above. Thanks!

Date

November 19, 2015

Response

Response

What about 2 more W6x15’s @
37.5” as in the clip – in the place of the standard posts at ¼ space.

For post 5 of our original
sketch fix: the below would span the footing but we would use an additional
6’-3” of thrie beam & the 31” rail to the right as in our original
sketch.

For post 6 fix: this would require moving the last W6x15 8” which would
be behind the 6-‘-3” thrie beam

The noted transition below does
not have include the transition to the standard AGT that is now used. However
and in terms of our prior discussion, one could add a few more ½-post spacings
of W6x15, another 6 ft 3 in. segment of thrie to include 12 ft 6 in. of single
thrie, then the asymmetric segment, etc. The 37.5 in. span would straddle the
hazard. You would still then have Scott’s stiffness transition with 18.75”
spacings and design K or L of prior report. Let me know if this makes sense. If
not we could sketch on paper a few versions.

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